1. Field of the Invention
The invention relates to a vehicle lifting system and more specifically to a system comprising one or more moveable lifts or lifting devices, such as lifting columns. In general, lifting systems are specifically used for lifting trucks and busses or other vehicles.
2. Description of Related Art
A lifting column known from practice comprises a frame with a carrier that is connected to a drive for moving the carrier upwards and downwards. In the ascent mode, hydraulic oil is pumped to a cylinder for lifting the carrier and, therefore, the vehicle. In the descent mode, the carrier with the vehicle is lowered and hydraulic oil returns to the reservoir. Such prior art lifting system is disclosed in U.S. Patent Application Publication No. 2006/0182563, which is incorporated herein by reference.
Known systems for lifting and lowering a vehicle often include a number of moveable lifting columns that communicate wireless with each other. Correct operation of the lifting system depends on correct and reliable communication of wireless signals. In a workshop wireless signals can be disturbed by large structures, such as vehicles, and other wireless devices sending and receiving signals. Due to disturbed communication lifting systems do not operate effectively and hazardous situations may result from such disturbed communication.
An object of the invention is to obviate or at least reduce some of the above problems.